Heretofore, in general, polyvinylidene chloride (PVDC) has been used as the material for wrapping and packaging hams, sausages, etc.
However, polyvinylidene chloride is problematic in that it produces chlorine gas when incinerated. With the recent increase in the awareness of environmental problems, it is much desired that conventional wrapping and packaging materials of chlorine resins are substituted with any others that are gentle to the environment.
Forming conventional wrapping and packaging materials into bags requires high-frequency sealing machines for high-temperature heat sealing.
To open them, bags of conventional wrapping and packaging materials are not easy to tear by hand.
A system of casing sausages is known, in which the cases formed are fixed with metal bands of aluminium or the like around their upper and lower sides. However, as having the metal bands, the cases are problematic in that they could not be applied to metal detectors for detecting impurities.